University of Tehran 1 Interface Design Vehicle Busses Omid Fatemi

University of Tehran 2 Outline

University of Tehran 3 Busses Computer buses Peripheral buses Instrumentation buses Vehicle buses

University of Tehran 4 Vehicle Buses? Why buses in vehicles? –Number of electronic equipments is increasing heavily in vehicles (expensive wiring) –Modern vehicles control system needs a lot of information from sensors –Easier fault diagnostic (tester can be connected to a single plug)

University of Tehran 5 Wire Length

University of Tehran 6

University of Tehran 7 Why Multiplex Wiring?

University of Tehran 8 Classification

University of Tehran 9 General Characteristics Typically short buses (no hierarchy) Open topology to provide easy addition of new modules and removing of old modules Broadcast type of transmission is typically used –(messages are sent to bus to be available for everybody) Immune for high noise –(temperature area -40 C to +125 C) Cheap price

University of Tehran 10 Protocol For Vehicle Buses CAN (Controller Area Network) –most European vehicle –both classB & classC LIN (Local Area Network) –all vehicles in future –classA VAN (Vehicle Area Network) –French vehicles (Renault, …) –both classB & classC

University of Tehran 11 Protocol For Vehicle Buses (Con) ABUS –VW D2B () –Mercedes –classD TTP(Time Trigger Protocol)

University of Tehran 12 CAN Protocol

University of Tehran 13 Basic properties Fast (up to 1Mbps) Prioritization Configuration flexibility Multi master Multicast Powerful error detection

University of Tehran 14 CAN in passenger car

University of Tehran 15 CAN Implementation

University of Tehran 16 CAN node

University of Tehran 17 Integration levels Stand alone controller Integrated controller Single chip CAN node

University of Tehran 18 Stand alone controller Software

University of Tehran 19 Integrated controller Easy PCB design Low cost High speed access (using internal bus)

University of Tehran 20 Single-chip node Different technologies on single chip

University of Tehran 21 CAN Physical layer

University of Tehran 22 Medium Attachments High speed CAN (ISO ) Low speed CAN (ISO ) Single wire (SEA2411) Fiber optical transmission Wireless transmission

University of Tehran 23 Network setup

University of Tehran 24 Twisted pair

University of Tehran 25 EMI interference

University of Tehran 26 CAN Connector 1. nc 2. CAN L 3. CAN GND 4. nc 5. CAN-shield 6. GND 7. CAN H 8. nc 9. CAN V+

University of Tehran 27 CAN Data link layer

University of Tehran 28 Broadcast communication

University of Tehran 29 Wired-and Mechanism

University of Tehran 30 Collision resolution bitwise arbitration CSMA/CD (carrier sense multiple access / collision detection)

University of Tehran 31 Arbitration

University of Tehran 32 Data rate 1 Mbps for bus length of up to 40m. 500 Kbps for bus length of up to 100m. 250 Kbps for bus length of up to 200m. 125 Kbps for bus length of up to 500m

University of Tehran 33 Frame types Data frame Remote frame Error frame Overload frame

University of Tehran 34 Data frame

University of Tehran 35 Arbitration field

University of Tehran 36 Control field

University of Tehran 37 CRC field

University of Tehran 38 ACK field

University of Tehran 39 Error handling Bit error Stuff error CRC error Form error ACK error